1. Field of the Invention
The invention relates to a position finding system, a use of the position finding system, and a method for determining position.
2. Description of the Background Art
Such a system is known from DE 10 2006 004 938 A1. The position finding system described therein is used for determining the position of a vehicle, for example. RFID transponders are used by preference for this purpose. Another position finding system is known from WO 2008/101702, which corresponds to US 2010/0141244. There, the induction in a sensor from a magnet located on a wheel is sensed in order to determine the position of the wheel. Another position finding system is known from DE 10 2008 044 739 A1, which corresponds to US 2010/0308803, and in which the position of a first object relative to a second object is determined by means of an inductive linear encoder. To this end, a sensor unit travels at close range past a marking section designed as a transmitter unit, wherein the marking section has a plurality of sections of metallic material of different widths. The sections of metallic material of different widths produce different intensities of induction. Another device and method for determining position is known from WO 2005/012840, which corresponds to U.S. Pat. No. 7,245,121. Using the method described therein, a sensor is used to analyze the induction produced in the sensor by permanent magnets, wherein the sensor unit located in a read head is capable of detecting the induction from multiple magnets at once.
In addition, a roller used in printing as a transmitter unit is known from DE 20 2007 004 717 U1, which roller also has an RFID transponder in addition to a magnet as reference mark. By means of the RFID transponder, the roller data stored on the transponder are read by the sensor unit, while the rotary position of the roller can be determined by means of the reference mark.
Another position finding system is known from EP 0 472 028 A2. There, RFID marks on a carrier device are detected by means of an RFID reader unit in order to cause directional changes or stops of the carrier device. In addition, an inductively operating detector unit is used to detect a deviation from a preferred direction. Additional systems are known from EP 1 577 188 A2, which corresponds to U.S. Pat. No. 7,426,424, and EP 1 770 373 A2, which corresponds to US 2007/074416, and US 2002/129508 A1. Moreover, a position finding system is also known from WO 2005/052842.
It is a disadvantage in the prior art position finding systems that the position cannot be determined immediately at any point in time, and/or the position finding systems are costly to manufacture and use, in particular in crane systems in port areas, for example, when the crane must traverse distances of several 100 m and the exact position must be determined at the same time. This also applies to use as a rotary encoder for rings with diameters larger than several meters.